Liquid cooling system for a rotating member

ABSTRACT

A self-pumping, liquid coolant system for a rotating member having a passageway therethrough; and a pair of rotating cups, one on either side of the rotating member and in communication with the passageway. An inlet means out of contact with the liquid level of one rotating cup and an outlet means submerged within the liquid level of the other rotating cup create a pressure differential effecting the self-pumping action.

hited States Patent Dicic Sept. 25, 1973 [54] LIQUID COOLING SYSTEM FOR A 3,241,331 3/1966 Eudress 62/505 ROTATING MEMBER 3,579,006 5/1971 Kindl 310/227 Inventor: Zoran Dicic, Schenectady, NY.

Assignee: General Electric Company,

Schenectady, NY.

Filed: Apr. 7, 1971 Appl. No.: 131,951

11.8. CI. 62/505, 310/227 int. Cl. F251) 31/00 Field of Search 165/47, 106, 107;

References Cited UNITED STATES PATENTS 4/1963 Robinson ..62/505 9/1964 Anderson ..62/505 Primary ExaminerMeyer Perlin Attorney-William C. Crutcher, James W. Mitchell, Frank L. Neuhauser, Oscar B. Waddell and Joseph B. Forman [5 7 ABSTRACT A self-pumping, liquid coolant system for a rotating member having a passageway therethrough; and a pair of rotating cups, one on either side of the rotating member and in communication with the passageway. An inlet means out of contact with the liquid level of one rotating cup and an outlet means submerged within the liquid level of the other rotating cup create a pres.- sure differential effecting the self-pumping action.

41 Claims, 2 Drawing Figures PATENTEUSEPZSHYS INVENTOR'. ZORAN DICIC, BY W M/M HIS ATTORNEY.

LIQUID COOLING SYSTEM FOR A ROTATING MEMBER BACKGROUND OF THE INVENTION This invention relates generally to cooling rotating members which are subject to heat accumulation due to buildup of electrical current density or high working fluid temperatures. For example, this invention has application to current collector rings, generator rotors, turbine rotors, and the like.

One limiting factor in the design of large machinery is the problem of heat accumulation in rotating members. Design parameters demand that a cooling system include as little hardware as possible due to space considerations and yet, a high degree of reliability is required.

In the past, various cooling systems have been proposed. These cooling systems were either gaseous cooling systems, liquid cooling systems or a combination thereof. Under liquid cooling systems, the liquid coolant has been pumped from sources external to a large machine, into the machine and then out of the machine. This type of system is disadvantageous because if the pump becomes inoperative, then there is the pos sibility of a power outage or even more disastrous, a fire hazard. To remedy this insufficiency, it has been proposed that a stand-by pump be included in the design. However, this results in an increase in hardware, and a requirement that means be provided to automatically activate. the stand-by pump when the normally used pump becomes inoperative.

Another proposal for large machine cooling has been the design of a self-pumping unit. This type of unit eliminates the need for a pump and insures reliability because the system is energized by the rotation of the machine. In U.S. Pat. application Ser. No. 878,746, filed Nov. 21, 1969, by Kindl et al., now matured into U. S. Pat. No. 3,579,006, and assigned to the assignee of the present application, such a self-pumping system has been described. The operation of the Kind] et al in vention is such that supply and pickup rings communicating with a liquid passageway are motivated by the velocity head of the rotating passageway to effect 'a self-pumping action.

The present invention differs in that the self-pumping action effected is derived by relative differences in pressure heads developed at the inlet and the outlet of a rotating liquid passageway. The particular structure by which this self-pumping action is effected will be described in this application.

OBJECTS OF THE INVENTION It is an object of this invention to provide a cooling system for a large machine having rotating members subject to heat accumulation.

It is an object of this invention to provide a liquid cooling system which will be self-pumping.

It is an object of this invention to provide a liquid cooling system which will be operative whenever the rotating machine is operative.

Further advantages will be apparent from the following description of one embodiment of the invention and the novel features will be pointed out hereinafter in the claims.

SUMMARY OF THE INVENTION A passageway is provided through the interior of a rotating machine part so that the liquid coolant may pass therethrough thereby cooling the rotating part. An inlet is provided out of contact with the rotating passageway. An outlet is provided and partially submerged within the rotating passageway. As liquid coolant contacts the sides of the submerged outlet, the velocity head decreases, creating a corresponding pressure drop at the outlet which results in a self-pumping flow of coolant from the high pressure inlet to the low pressure outlet. The liquid coolant then may be cooled and recirculated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of a rotating machine, partially sectioned to show the present invention applied thereto.

FIG. 2 is a cross section taken at 11-" on FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2, a shaft 11 rotates a member to be cooled shown generally at 13. The rotating member may be comprised of three sections: a center section 15 and two end overhanging sections 17 and 19, which form respectively rotating cups A and B.

At one end of the shaft, there is an inlet means 21 which includes a stationary annular hollow ring 23 coaxially mounted about the shaft but not rotatable therewith; a double disk construction 25 positioned inside the one end section 17 of the rotating member, and a double wall pipe 27 which connects the hollow annular ring with the double disk in such a manner as to enable a liquid coolant to flow from the hollow ring through the double wall pipe, into the double disk construction and then into rotating cup A. It should be noted that the double disk construction 25 does not extend into the liquid level A, of the rotating cup A liquid content.

At the other end of the shaft, there is an outlet means 31 which includes a stationary annular hollow ring 33 coaxially mounted about the shaft, but not rotatable therewith; a double disk construction 35 positioned inside the other end section 19 of the rotating member and a double wall pipe 37 which connects the hollow ring with the double disk in such a manner as to enable liquid coolant flowing from the rotating cup B into the double disk 35 to be delivered through the double wall pipe 37 into the hollow ring. It should be noted that the double disk construction 35 extends into the liquid level B, of the rotating cup B liquid content. I A liquid passageway 39 through the central section of the rotating member 13 connects cup A with cup B. The center section 15 of the rotating member may represent a collector ring, generator windings, or any other rotating machine part to be cooled. The liquid passageway 39 may be comprised of several passageways which are not necessarily on the same radius, but which may be sinuous or have bends in them to and from different radii from the axis of rotation and represent cooling passages in the member to be cooled.

An exterior flow system comprises an outlet pipe 41 passing from an opening in the hollow ring 33 to transport heated liquid coolant from the interior of the member to a heat exchanger 43, where it is cooled. Then the liquid coolant is passed to an inlet pipe 45 connected to the hollow ring 23 where the liquid coolant is recirculated through the member 13. There may be a valve 47 to control the flow ofliquid coolant about a greater outer diameter. This particular construction facilitates the liquid pickup from rotating cup B.

Although the inlet 25 is shown as a double disk, this is not necessary since there is no contact with the liquid. A simple inlet pipe will also be satisfactory.

The manner and principles of operation of applicants invention are as follows: Liquid coolant is fed into the system so that when the rotating member is up to speed, centrifugal forces distribute the liquid coolant against the inner circumference of the rotating member 13 as shown in rotating cups A and B having liquid levels A and B,, and liquid passageway 39. The selfpumping effect of the liquid coolant is from rotating cup A to rotating cup B, both cups being equal in size.

In cup A, the pressure developed due to the rotational velocity of cup A is greater than the pressure developed in cup B due to a rotational velocity of the cup B. The reason this is so, is because the double disk construction 35 in cup B is set into the rotating liquid of cup B, thereby reducing the rotational velocity of the liquid surrounding the double disk to one-half, and also reducing the velocity of the liquid at the disk walls to zero. Since the double disk construction 25 for cup A remains out of contact with the liquid level in cup A, no such reduction in rotational velocity occurs. Thus, the ratio of the velocity of the liquid in cup A to the rotational velocity of the liquid in cup B is given as:

[i (velocity of fluid in cup with disk/velocity of fluid in cup without disk) 1.00.

Inserting this ratio into a general pressure equation for cup A and B wherein dp pw rdr the following results:

Pressure A (p/2) 2 c Pressure B (p/2) (,8

Thus, it is apparent that the pressure in cup B is less thanthe pressure in cup A, thereby causing a flow of liquid coolant from cup A to cup B, effecting a selfpumping action.

The liquid flow from cup A to cup B is transported about the exterior flow system where it is cooled and then recirculated through the rotating member.

While there is shown what is considered at present to be the preferred embodiment of the invention, it is of course understood that various other modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention. What is claimed is:

l. A self-pumping liquid coolant system for cooling rotating members of a rotating machine including a rotating shaft and a rotating member comprising:

a pair of rotating cups, one on either side of said rotating member having a liquid coolant level when said rotating member is up to speed;

a passageway passing through said rotating member interconnecting said pair of rotating cups;

a stationary inlet means, being out of contact with the liquid coolant level in one of said rotating cups;

a stationary outlet means including an annular hollow ring and a double disk construction, the latter being partially submerged within the liquid coolant level of the other said rotating cup; the annular hollow ring and the double disk construction connected by a double wall pipe; and,

an exterior flow system having control systems for cooling and recirculating liquid coolant through the rotating members.

2. In a rotating machine having a rotating shaft and a rotating member to be cooled driven by said rotating shaft, a self-pumping liquid coolant system for cooling said rotating member comprising:

an exterior coolant flow system with means to recirculate and cool a liquid coolant;

a pair of rotating cups, defined at substantially the same distance from the axis of said rotating member, having a liquid coolant level when said rotating member is up to speed;

at least one passageway passing through said rotating member interconnecting said pair of rotating cups;

a stationary inlet means including an annular, hollow ring disposed about said rotating shaft; a double disk construction disposed within said rotating member but out of contact with said liquid coolant level of one said rotating cup; and, a double wall pipe connecting said double disk construction with said annular hollow ring member;

a stationary outlet means partially submerged within said liquid coolant level of the other said rotating cup; and,

said inlet and outlet means being connected in a continuous circuit through said exterior flow system.

3. In a rotating machine having a rotating shaft and a rotating member to be cooled driven by said rotating shaft,'a self-pumping liquid coolant system for cooling said rotating member comprising:

an exterior coolant flow system with means to recirculate and cool a liquid coolant;

a pair of rotating cups, defined at substantially the same distance from the axis of said rotating member, having a liquid coolant level when said rotating member is up to speed;

at least one passageway passing through said rotating member interconnecting said pair of rotating cups;

a stationary inlet means out of contact with said liquid coolant level of one said rotating cup;

a stationary outlet means including an annular hollow ring disposed about said rotating shaft; a double disk construction disposed within said rotating member, partially submerged below said liquid coolant level of the other said rotating cup; and, a double wall pipe connecting said double disk construction with said annular hollow ring member; and,

said inlet and outlet means being connected in a continuous circuit through said exterior flow system.

4. The self-pumping liquid coolant system as recited in claim 3 wherein the double disk construction includes two axially concentric disks the outer radius of the disk closer the passageway smaller than the outer radius of the disk further from the passageway. 

1. A self-pumping liquid coolant system for cooling rotating members of a rotating machine including a rotating shaft and a rotating member comprising: a pair of rotating cups, one on either side of said rotating member having a liquid coolant level when said rotating member is up to speed; a passageway passing through said rotating member interconnecting said pair of rotating cups; a stationary inlet means, being out of contact with the liquid coolant level in one of said rotating cups; a stationary outlet means including an annular hollow ring and a double disk construction, the latter being partially submerged within the liquid coolant level of the other said rotating cup; the annular hollow ring and the double disk construction connected by a double wall pipe; and, an exterior flow system having control systems for cooling and recirculating liquid coolant through the rotating members.
 2. In a rotating machine having a rotating shaft and a rotating member to be cooled driven by said rotating shaft, a self-pumping liquid coolant system for cooling said rotating member comprising: an exterior coolant flow system with means to recirculate and cool a liquid coolant; a pair of rotating cups, defined at substantially the same distance from the axis of said rotating member, having a liquid coolant level when said rotating member is up to speed; at least one passageway passing through said rotating member interconnecting said pair of rotating cups; a stationary inlet means including an annular, hollow ring disposed about saId rotating shaft; a double disk construction disposed within said rotating member but out of contact with said liquid coolant level of one said rotating cup; and, a double wall pipe connecting said double disk construction with said annular hollow ring member; a stationary outlet means partially submerged within said liquid coolant level of the other said rotating cup; and, said inlet and outlet means being connected in a continuous circuit through said exterior flow system.
 3. In a rotating machine having a rotating shaft and a rotating member to be cooled driven by said rotating shaft, a self-pumping liquid coolant system for cooling said rotating member comprising: an exterior coolant flow system with means to recirculate and cool a liquid coolant; a pair of rotating cups, defined at substantially the same distance from the axis of said rotating member, having a liquid coolant level when said rotating member is up to speed; at least one passageway passing through said rotating member interconnecting said pair of rotating cups; a stationary inlet means out of contact with said liquid coolant level of one said rotating cup; a stationary outlet means including an annular hollow ring disposed about said rotating shaft; a double disk construction disposed within said rotating member, partially submerged below said liquid coolant level of the other said rotating cup; and, a double wall pipe connecting said double disk construction with said annular hollow ring member; and, said inlet and outlet means being connected in a continuous circuit through said exterior flow system.
 4. The self-pumping liquid coolant system as recited in claim 3 wherein the double disk construction includes two axially concentric disks the outer radius of the disk closer the passageway smaller than the outer radius of the disk further from the passageway. 